Developing bit torrent client (Centralized unstructured P2P)

Question

I want to develop a bit torrent client (centralized unstructured peer to peer) . I have a knowledge about networking and experience in developing some test programs in C#(networking) . The module I want to create is capable of creating torrent files also. and I want to create the GUI using WPF.
But the problem is I never develop any software like this,I developed web applications this is new for me..Just tell me the approach I have to take for development of this software, and give some information about which technologies I have to study and what is the function of that technology in my software.
Pls help me on this